Modelling the hydrological behaviour of a coffee agroforestry basin in Costa Rica

Gomez Delgado Federico, Roupsard Olivier, Le Maire Guerric, Taugourdeau Simon, Pérez A., Van Oijen Marcel, Vaast Philippe, Rapidel Bruno, Harmand Jean-Michel, Voltz Marc, Bonnefond Jean-Marc, Imbach Pablo, Moussa Roger. 2011. Modelling the hydrological behaviour of a coffee agroforestry basin in Costa Rica. Hydrology and Earth System Sciences, 15 (1) : 369-392.

Quartile : Q1, Sujet : WATER RESOURCES / Quartile : Q1, Sujet : GEOSCIENCES, MULTIDISCIPLINARY

Résumé : The profitability of hydropower in Costa Rica is affected by soil erosion and sedimentation in dam reservoirs, which are in turn influenced by land use, infiltration and aquifer interactions with surface water. In order to foster the provision and payment of Hydrological Environmental Services (HES), a quantitative assessment of the impact of specific land uses on the functioning of drainage-basins is required. The present paper aims to study the water balance partitioning in a volcanic coffee agroforestry micro-basin (1 km2, steep slopes) in Costa Rica, as a first step towards evaluating sediment or contaminant loads. The main hydrological processes were monitored during one year, using flume, eddy-covariance flux tower, soil water profiles and piezometers. A new Hydro-SVAT lumped model is proposed, that balances SVAT (Soil Vegetation Atmosphere Transfer) and basin-reservoir routines. The purpose of such a coupling was to achieve a trade-off between the expected performance of ecophysiological and hydrological models, which are often employed separately and at different spatial scales, either the plot or the basin. The calibration of the model to perform streamflow yielded a NS coefficient equal to 0.80, while the validation of the water balance partitioning was consistent with the independent measurements of actual evapotranspiration (R2=0.79, energy balance closed independently), soil water content (R2=0.49) and water table level (R2=0.90). An uncertainty analysis showed that the streamflow modelling was precise for nearly every time step, while a sensitivity analysis revealed which parameters mostly affected model precision, depending on the season. It was observed that 64% of the incident rainfall R flowed out of the basin as streamflow, 25% as evapotranspiration and the remaining 11% was attributed to deep percolation. The model indicated an interception loss equal to 4% of R, a surface runoff of 5% and an infiltration component of 91%. The modelled streamflow was constituted by 63% of baseflow originating from the aquifer, 29% of subsurface non-saturated runoff and 8% of surface runoff. Given the low surface runoff observed under the current physical conditions (andisol) and management practices (no tillage, planted trees, bare soil kept by weeding), this agroforestry system on a volcanic soil demonstrated potential to provide valuable HES, such as a reduced superficial displacement-capacity for fertilizers, pesticides and sediments, as well as a streamflow regulation function provided by the highly efficient mechanisms of aquifer recharge and discharge. The proposed combination of experimentation and modelling across ecophysiological and hydrological approaches proved to be useful to account for the behaviour of a given basin, so that it can be applied to compare HES provision for different regions or management alternatives.

Mots-clés Agrovoc : agroforesterie, Coffea, service, modèle de simulation, hydrologie

Mots-clés géographiques Agrovoc : Costa Rica

Mots-clés complémentaires : Service environnemental

Classification Agris : U10 - Informatique, mathématiques et statistiques
P10 - Ressources en eau et leur gestion
F08 - Systèmes et modes de culture
K10 - Production forestière

Champ stratégique Cirad : Axe 6 (2005-2013) - Agriculture, environnement, nature et sociétés

Auteurs et affiliations

• Gomez Delgado Federico, CIRAD-PERSYST-UPR Ecosystèmes de plantations (CRI)
• Roupsard Olivier, CIRAD-PERSYST-UPR Ecosystèmes de plantations (CRI) ORCID: 0000-0002-1319-142X
• Le Maire Guerric, CIRAD-PERSYST-UPR Ecosystèmes de plantations (FRA) ORCID: 0000-0002-5227-958X
• Taugourdeau Simon ORCID: 0000-0001-6561-3228
• Pérez A.
• Van Oijen Marcel, CEH (GBR)
• Vaast Philippe, CIRAD-PERSYST-UPR Ecosystèmes de plantations (IND)
• Rapidel Bruno, CIRAD-PERSYST-UMR SYSTEM (CRI) ORCID: 0000-0003-0288-5650
• Harmand Jean-Michel, CIRAD-PERSYST-UPR Ecosystèmes de plantations (FRA) ORCID: 0000-0002-8065-106X
• Voltz Marc
• Bonnefond Jean-Marc, INRA (FRA)
• Imbach Pablo, CATIE (CRI)
• Moussa Roger, INRA (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/558470/)

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